1. Field of the Invention
The present invention relates to a substrate processing apparatus and a substrate processing method for processing a semiconductor substrate or a glass substrate.
2. Description of the Prior Art
A substrate processing apparatus accommodates a substrate (wafer) to be processed inside a reaction chamber, controls a heater to heat the inside of the reaction chamber to a predetermined temperature, supplies gas into the reaction chamber, if necessary, adjusts an internal pressure of a heating furnace, and processes the substrate while rotating a boat which holds the substrate. In the substrate processing apparatus, a Mass Flow Controller (MFC) is installed to adjust and control a flow rate of a reaction gas supplied into the reaction chamber.
However, there may occur a zero point misalignment of the MFC, a malfunction of a flow rate sensor installed inside the MFC, and a malfunction of a valve installed inside the MFC or an actuator for actuating the valve. In this case, since a gas flow rate varies, the processing of the substrate is adversely affected to cause quality, yield and safety problems.